The Facts on Magic

"The art of producing illusions as entertainment by the use of sleight of hand, deceptive devices, etc.; legerdemain; conjuring."

This is not what Witches do; there is no illusion or sleight of hand taking place in witchcraft, there is connection to an unseen force; the natural world, to create a change in ones world around them.

the art of producing a desired effect or result through the use of incantation or various other techniques that presumably assure human control of supernatural agencies or the forces of nature.

While this definition does include some of what a witch does, I wouldn't say that it's entirely conclusive or accurate. We can't assure that we have control over supernatural forces and most DEFINITELY not the forces of nature. No one has control over nature, she's a force in of herself. Witches desire to work with nature, to petition it in our favor, not over it.

The creation of the word Magick:

One of the first witch books I read, stated that magick was spelled as such to differentiate between stage magic, slight of hand, and magick that creates a change in the world of the witch. Most if not all serious witchcraft themed books I have read since spell it as Magick.

My Conclusion

Really it's up to you how you spell it; magick or magic. Personally I prefer the spelling as Magick because not one bit of what I do has anything to do with "tricks" on stage that astound the audience. I include both spellings in my posts because a lot of new witches spell it without the "k" because they haven't yet made up their mind, or maybe don't know, about the two different spelling.